Dancing sea lion surprises scientists [Video]

A California sea lion is the first nonhuman mammal known to keep a beat, suggesting the roots of rhythm may run deeper than previously thought.

More research will be needed to know if Ronan's dancing skills are shared by other sea lions, such as this one at the Smithsonian's National Zoo in Washington. (Photo: Karen Bleier/AFP/Getty Images)

After rescuing a young sea lion from a busy highway in 2009, researchers at the University of California Santa Cruz realized she was different. It was already her third stranding incident in a year, but she nonetheless seemed smarter than other sea lions.

So the researchers did what anyone would do: They taught her how to dance.

Four years later, Ronan is the first nonhuman mammal with a proven ability to keep a beat. While some birds can keep time with manmade music, as Snowball the cockatoo famously demonstrated, sea lions now join humans as the only mammals known to synchronize their dance moves with an external rhythm.

"From my first interactions with her, it was clear that Ronan was a particularly bright sea lion," says Peter Cook, a grad student at UC Santa Cruz and lead author of a new study about Ronan. "Everybody in the animal cognition world, including me, was intrigued by the dancing bird studies, but I remember thinking that no one had attempted a strong effort to show beat keeping in an animal other than a parrot. I figured training a mammal to move in time to music would be hard, but Ronan seemed like an ideal subject."

It turns out she was, as the video below illustrates:

Whether she's grooving to "Boogie Wonderland" or the Backstreet Boys, Ronan's moves undermine a popular theory that suggests beat keeping (formally known as "rhythmic entrainment") requires a capacity for complex vocal learning. People and parrots can keep a beat, according to this theory, because our brains are wired for speech.

"Ronan's success poses a real problem for the theory that vocal mimicry is a necessary precondition for rhythmic entrainment," Cook says in a press release about the research. "The idea was that beat keeping is a fortuitous side effect of adaptations for vocal mimicry, which requires matching incoming auditory signals with outgoing vocal behavior. It's understandable why that theory was attractive. But the fact is our sea lion has gotten really good at keeping the beat."

Teaching sea lions to sway wasn't Cook's primary academic project — he also studies the cognitive effects of neurotoxins produced by algae — so he and research technician Andrew Rouse mostly held Ronan's dance lessons on weekends. They started with simple rhythm tracks, and it took a few months before she could reliably keep a beat. Once she mastered the skill, though, she surprised her teachers with an uncanny ability to keep time with novel tempos and songs she'd never heard before.

"Given her success at keeping the beat with new rhythm tracks and songs following her initial training, it's possible that keeping the beat isn't that hard for her," Cook says. "She just had to learn what it was we wanted her to do."

And now that she's found rhythm, Cook adds, Ronan has become a more consistent dancer than many beat-keeping birds. "In the videos, Alex [an African gray parrot] and Snowball fall off the beat a lot," Cook says. "They're good at finding the tempo in music, but don't seem to maintain the behavior as reliably as Ronan. She stays right on the beat."

That could have big implications for the biological roots of music, since previous research can't quite explain Ronan's moves. Scientists used to think rhythmic entrainment was uniquely human, but dancing parrots like Snowball threw that idea out the window. More recent theories have suggested birds' vocal mimicry skills enable dancing, but now a head-banging sea lion — a species that doesn't mimic vocal sounds, the study's authors note — may force yet another rethink of rhythm in the animal kingdom.

"Human musical ability may in fact have foundations that are shared with animals," Cook says. "People have assumed that animals lack these abilities. In some cases, people just hadn't looked."